I would hate that. I feel for you. The not calling thing really pisses me off.
Sure, he may be busy. Or he may have lost his balls and is just avoiding you. Hopefully it isn't that.
You could call him and let him know that you're getting annoyed. Let him know that you're interested and that you don't want to continue to call if he isn't. Nobody wants to be a pain in the ass. After this call if he still doesnt call back it's probably best to shut the books on this one.
I hope he contacts you